Friday, 25 September 2015

I've wanted a stand-alone radio in my office for a long time. I've been using a small portable radio, but it ate batteries quickly (probably a 4-pack of AA for a bit less of a work week's worth of listening), changing stations was cumbersome (hello FM dials) and the speaker was a bit teeny.

A couple of years back, I had a Raspberry Pi-based computer on pre-order (the Kano, highly recommended for kids, and beginners) through a crowd-funding site. So I scoured « brocantes » (imagine a mix of car boot sale and antiques fair, in France, with people emptying their attics) in search of a shell for my small computer. A whole lot of nothing until my wife came back from a week-end at a friend's with this:

I started by removing the internal parts of the radio, without actually turning it on. When you get such old electronics, they need to be checked thoroughly before being plugged, and as I know nothing about tube radios, I preferred not to. And FM didn't exist when this came out, so not sure what I would have been able to do with it anyway.

Roomy, and dirty. The original speaker was removed, the front buttons didn't have anything holding them any more, and the nice backlit screen went away as well.

To replace the speaker, I went through quite a lot of research, looking for speakers that were embedded, rather than get a speaker in box that I would need to extricate from its container. Visaton make speakers that can be integrated into ceiling, vehicles, etc. That also allowed me to choose one that had a good enough range, and would fit into the one hole in my case.

To replace the screen, I settled on an OLED screen that I knew would work without too much work with the Raspberry Pi, a small AdaFruit SSD1306 one. Small amount of soldering that was up to my level of skills.

It worked, it worked!

Hey, soldering is easy. So because of the size of the speaker I selected, and the output power of the RPi, I needed an amp. The Velleman MK190 kit was cheap (€10), and should just be able to work with the 5V USB power supply I planned to use. Except that the schematics are really not good enough for an electronics starter. I spent a couple of afternoons verifying, checking on the Internet for alternate instructions, re-doing the solder points, to no avail.

Finally, I got another Raspberry Pi, and SD card, so that the Kano, with its super wireless keyboard, could find a better home (it went to my godson, who seemed to enjoy the early game of Pong, and being a wizard).

Putting it all together

We'll need to hold everything together. I got a bit of help for somebody with a Dremel tool for the piece of wood that will hold the speaker, and another one that will stick three stove bolts out of the front, to hold the original tuning, mode and volume buttons.

I fast-forwarded the machine by a couple of years with a « Philips » figure-of-8 plug at the back, so machine's electrics would be well separated from the outside.

Screws into the side panel for the amp, blu-tack to hold the OLED screen for now, RPi on a few leftover bits of wood.

Software

My first attempt at getting something that I could control on this small computer was lcdgrilo. Unfortunately, I would have had to write a Web UI for it (remember, my buttons are just stuck on, for now at least), and probably port the SSD1306 OLED screen's driver from Python, so not a good fit.

There's no proper Fedora support for Raspberry Pis, and while one can use a nearly stock Debian with a few additional firmware files on Raspberry Pis, Fedora chose not to support that slightly older SoC at all, which is obviously disappointing for somebody working on Fedora as a day job.

Looking for other radio retrofits, and there are plenty of quality ones on the Internet, and for various connected speakers backends, I found PiMusicBox. It's a Debian variant with Mopidy builtin, and a very easy to use initial setup: edit a settings file on the SD card image, boot and access the interface via a browser. Tada!

Once I had tested playback, I lowered the amp's volume to nearly zero, raised the web UI's volume to the maximum, and raised the amp's volume to the maximum bearable for the speaker. As I won't be able to access the amp's dial, we'll have this software only solution.

Wrapping up

I probably spent a longer time looking for software and hardware than actually making my connected radio, but it was an enjoyable couple of afternoons of work, and the software side isn't quite finished.

Secondly, Mopidy supports plugins to extend its sources, uses GStreamer, so would be a right fit for Grilo, making it easier for Mopidy users to extend through Lua.

Do note that the Raspberry Pi I used is a B+ model. For B models, it's recommended to use a separate DAC, because of the bad audio quality, even if the B+ isn't that much better. Testing out use the HDMI output with an HDMI to VGA+jack adapter might be a way to cut costs as well.

Possible improvements could include making the front-facing dials work (that's going to be a tough one), or adding RFID support, so I can wave items in front of it to turn it off, or play a particular radio.

In all, this radio cost me:
- 10 € for the radio case itself
- 36.50 € for the Raspberry Pi and SD card (I already had spare power supplies, and supported Wi-Fi dongle)
- 26.50 € for the OLED screen plus various cables
- 20 € for the speaker
- 18 € for the amp
- 21 € for various cables, bolts, planks of wood, etc.

I might also count the 14 € for the soldering iron, the 10 € for the Velleman amp, and about 10 € for adapters, cables, and supplies I didn't end up using.

So between 130 and 150 €, and a number of afternoons, but at the end, a very flexible piece of hardware that didn't really stretch my miniaturisation skills, and a completely unique piece of furniture.

In the future, I plan on playing with making my own 3-button keyboard, and making a remote speaker to plug in the living room's 5.1 amp with a C.H.I.P computer.

Wednesday, 23 September 2015

As I'm known to do, a focus on the little things I worked on during the just released GNOME 3.18 development cycle.

Hardware support

The accelerometer support in GNOME now uses iio-sensor-proxy. This daemon also now supports ambient light sensors, which Richard used to implement the automatic brightness adjustment, and compasses, which are used in GeoClue and gnome-maps.

In kernel-land, I've fixed the detection of some Bosch accelerometers, added support for another Kyonix one, as used in some tablets.

I've also added quirks for out-of-the-box touchscreen support on some cheaper tablets using the goodix driver, and started reviewing a number of patches for that same touchscreen.

With Larry Finger, of Realtek kernel drivers fame, we've carried on cleaning up the Realtek 8723BS driver used in the majority of Windows-compatible tablets, in the Endless computer, and even in the $9 C.H.I.P. Linux computer.

Bluetooth UI changes

The Bluetooth panel now has better « empty states », explaining how to get Bluetooth working again when a hardware killswitch is used, or it's been turned off by hand. We've also made receiving files through OBEX Push easier, and builtin to the Bluetooth panel, so that you won't forget to turn it off when done, and won't have trouble finding it, as is the case for settings that aren't used often.

Videos

GNOME Videos has seen some work, mostly in the stabilisation, and bug fixing department, most of those fixes were also landed in the 3.16 version.

We've also been laying the groundwork in grilo for writing ever less code in C for plugin sources. Grilo Lua plugins can now use gnome-online-accounts to access keys for specific accounts, which we've used to re-implement the Pocket videos plugin, as well as the Last.fm cover art plugin.

All those changes should allow implementing OwnCloud support in gnome-music in GNOME 3.20.

My favourite GNOME 3.18 features

You can call them features, or bug fixes, but the overall improvements in the Wayland and touchpad/touchscreen support are pretty exciting. Do try it out when you get a GNOME 3.18 installation, and file bugs, it's coming soon!

Talking of bug fixes, this one means that I don't need to put in my password by hand when I want to access work related resources. Connect to the VPN, and I'm authenticated to Kerberos.

I've also got a particular attachment to the GeoClue GPS support through phones. This allows us to have more accurate geolocation support than any desktop environments around.

A few for later

The LibreOfficeKit support that will be coming to gnome-documents will help us get support for EPubs in gnome-books, as it will make it easier to plug in previewers other than the Evince widget.

Victor Toso has also been working through my Grilo bugs to allow us to implement a preview page when opening videos. Work has already started on that, so fingers crossed for GNOME 3.20!